Spacecraft closes in on comet
 |
Workers at Kennedy Space Center in Florida watch as the Stardust spacecraft is lowered in January 1999.
Story Tools
|
PASADENA, California (AP) -- A speeding spacecraft has entered the bright halo of dust and gas surrounding a shimmering comet, where NASA hopes it will snag and return to Earth less than a thimbleful of primitive leftovers from the formation of our solar system.
The National Aeronautics and Space Administration said its Stardust spacecraft could pass within 186 miles of the comet Wild 2 on Friday while flying through the gossamer cloud that envelops the dirty ball of ice and rock.
Mission members expected the probe to make its closest approach at 2:40 p.m. EST, while traveling at a relative speed of 13,650 mph.
Stardust was designed to gather hundreds if not thousands of dust particles streaming from Wild 2 (pronounced Vilt-2) during the flyby 242 million miles from Earth.
NASA also planned for the unmanned spacecraft to snap 72 black-and-white close-ups of the comet's nucleus, thought to be just 3.3 miles across.
Mission members warned comet flybys are risky, given the violent battering dust particles can give a spacecraft. Engineers gave Stardust armored bumpers to shield it during the encounter.
Scientists want to return samples of the dust particles to Earth for study because they represent pristine examples of the building blocks of our solar system dating back 4.6 billion years. They also believe the dust contains many of the organic molecules necessary for life, which comets could have pelted the Earth with eons ago.
Altogether, Stardust was expected to collect a pile of dust too small to cover an adult's thumbnail, members of the $200 million mission said. They planned for Stardust to sweep back past the Earth in January 2006 and jettison a canister containing the dust-packed aerogel, allowing it to fall the ground in Utah.
If returned, the particles would represent the second robotic retrieval of extraterrestrial material since 1976, when the unmanned Soviet Luna 24 mission brought back samples of rock and soil from the moon. NASA's Genesis spacecraft should be the first since then come September, when it returns samples of the solar wind it has collected in space.
Copyright 2004 The
Associated Press. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.
